I am not good at electrical, but my friend who is, is (I think) planning to just interrupt the wire going to the relay (for a different purpose). You could probably cut the wire coming off the fuse, extend it through a hole in the firewall, and put an LED in line. Of course he is putting in an on/off toggle switch, not a light.

If you get one of the larger (~10mm dia) lights with built in bezel you can drill a hole in a blank dash panel and it will look OEM. Loose LED's are kinda hard to mount.

Heh... I always managed to run my amplifier power cable thru my fender and in between the door jam up front. More recently, I used the method to test out trying to hook up a Chevy Blazer Driver Info Center into my S10, because it was the easiest way to access the necessary wiring.

Just look at your firewall on the front side. There will be holes for heater hoses, HVAC, speedometer (if digital maybe not), steering column, etc. Most will have some sort of rubber o-ring deal to keep moisture out. Pick one that's easy to get to on either side- likely in the driver's foot well. I'd check out the steering column and pedal box first, since you probably wouldn't have to remove dash parts to pull a wire through.